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Best coolant to use

Discussion in 'Maintenance and Servicing' at netrider.net.au started by nnila, Jan 12, 2015.

  1. Hi all,
    My bike has been getting pretty hot recently and so I am thinking I will flush it and replace the coolant. I have a Triumph Daytona 675 (2006).

    What's the best coolant out there? Do the different brands make much of a difference or not? If I can pay more and keep the bike a lot cooler then I dont mind. I dont want to pay more however to get no real noticeable difference.


  2. any of the pre-mix stuff should be alright as long as it has corrosion inhibitors added.
    I wouldnt use the stuff from the discount stores, but anything from repco, or your bike shop or one of the auto shops will be fine.:]
    Hopefully that helps with the overheating problem. failing that it could be something as simple as a thermostat or sensor or something.
  3. Make sure the coolant that you use is silicate, borate and phosphate free, I use Nulon blue coolant pre-mix from Repco.
    Have heard some of the lower standard coolants that use silicates chewing out water pumps in the Motocross world.
  4. Water is the best coolant you can get, but then you need some chemicals to change the boiling/freezing point and inhibit rust.

    Any premixed coolant sold in a decent automotive shop will be fine.

    If you plan to attend track days you may want to check whether the track you wish to attend has any restrictions on coolant types.

    If you bikes running hot it is probably because the weather is warmer i.e. It is summer after all ;)

    You could turn you bike off when stationary for extended periods or gave your Ecuador to have the fans come on sooner.

    However if your bikes temps aren't in the red there is nothing to worry about.
  5. ethylene glycol & water mixture, 50% by vol roughly.

    It's summer, bikes run hotter in summer.
    If you are worried: check radiator fins, straighten them out if any are bent. Use a thermostat that opens at a lower temp. have the fan come on at a lower temp.

    [FLUX] removed the fan from his bike and said it didn't affect the running of the bike. His total riding weight had been reduced by 55 kg though, and he didn't do any commuting on it.
  6. What's your temperature reading, and what does the manual say? If it's still in the normal range then I wouldn't worry about it.
  7. Spoke to triumph today and they said it's normal and not a lot I can do about it and different coolants would make no difference. Commuting in this weather just kills them and makes them ready to cook your dinner on.
  8. #8 oldcorollas, Jan 12, 2015
    Last edited: Jan 12, 2015
    if there is space, you could try and modify the fan shrouding, so that it pulls air from a larger proportion of the radiator.
    may help with low speed cooling.

    coolant type will make little to no difference, is just a balance of heat in vs heat out

    edit: if it looks like this, not surprising that low speed cooling doesn't do much..
  9. An old mechanic once told me, "that so long as you don't lose the coolant, the temperature of the engine will be within the normal range. That gulping sound, of coolant being expelled is not what you want to hear. Otherwise, everything is OK."
    • Agree Agree x 1
  10. I agree that if you are using the correct pressure radiator cap and not losing coolant then you should be fine. However to answer the OP question which was about the BEST coolant, I think there are some differences you could research. As it was explained to me the anti-freeze chemical and the anti boil were somewhat different, and if you didn't need the antifreeze you could get just an anti boil that was supposed to be better (can't remember if it was a higher boiling point or less corrosive for the engine). I'm just going from memory so please forgive me if I've got the details wrong, but suffice to say there were supposed to be superior anti-boil products in a concentrate you mixed yourself rather than a premix.
  11. Ethylene Glycol is the "antifreeze/antiboil" agent in coolant generally. It is the same chemical. It can be coloured. It raises the boiling point and depresses the freezing point of water it is mixed with. However, has a lower specific heat (cannot store as much heat as water/volume). The 33% mix (the usual recommendation) is a compromise to get the best thermal conductivity from the coolant mix together with resistance to boiling or freezing. The reduction in the thermal properties of the coolant mixture is generally taken into account in engineering the cooling system of engines, so there is a specific recommendation for the % that should be used.

    Where temperatures are really cold (-30 or lower) the coolant may be 60% or more E.G. Engine cooling is not an issue, but the water freezing is. If one were to use 60%, or more in an engine in a hot climate, the subsequent reduction in the ability of the coolant mix to conduct heat means that a larger capacity radiator may need to be used to retain the overall efficiency of the system to move and dispose of the heat from the engine.

    Pure Water (deionized or distilled) + Ethylene glycol = the best coolant, used at the motorcycle manufacturer recommended %. I think the additives are mostly snake oil.
    • Agree Agree x 2
    • Informative Informative x 2
  12. What exactly is wrong with the one in that picture? Not sure what I'm meant to be looking at with it.
  13. compare left image (no shroud) to right image here (shroud).

    with no shroud, the fan only pulls air through a fan sized portion of the radiator.
    with shroud, air is pulled through a larger proportion of the radiator, and this is better..


    partial shroud is better than no shroud

    full shroud is more efficient

    bikes don't tend to have big shrouds, because they don't tend to be designed to spend a lot of time sitting still or at low speed..
    • Like Like x 1
  14. nothing wrong with stock setup, when bike is used as intended :)
    • Agree Agree x 1
  15. Fit one of those water misting nozzles you see on those fans used to cool outdoor areas, with a car windscreen washer motor that activates when the radiator fan kicks in.

    Just remember to top up the water bottle.
  16. I'd also suggest (first) actually measuring the real temp.. gauges are notoriously arbitrary (ie, not linear) in their representation of temperature.
    an infrared thermometer aimed at inlet and outlet of radiator will give a reasonable idea. black surface more reliable than shiny aluminium surface.

    maybe "hot" is still within decent temp range?
  17. For the Street Triple the manual says HD4X Hybrid OAT and I suspect the Daytona needs the same. I think this is a Triumph product so may be exxy. I think the mechanic put a high end Motul one in mine.
  18. For sure get the type specified, and don't skimp on brand/quality.

    With the modern engines and coolants now, you can get years without having to replace. Decent mechanics can check now and deem the coolant to be fine, rather than change it strictly by the book whether it needs it or not.

    Also, even if the radiator looks clean, a GENTLE blow out with a compressed air nozzle may remove fine dust and other light crap accumulated in the tiny places that can affect cooling performance.
  19.  Top
  20. #20 oldcorollas, Jan 14, 2015
    Last edited: Jan 14, 2015
    better than what?

    likely because the heat capacity of the non-water stuff is lower, meaning you need a bigger radiator, or it runs hotter...
    I thought you didn't want it to run hotter?

    Evans is (afaik) a mixture of ethylene glycol, and propylene glycol... so basically running "coolant" at 100% concentration, with lower heat capacity than a water/glycol mix, and you will need a larger or more efficient radiator to have the same level of cooling as a normal mix...

    does it prevent localised boiling from hotspots? probably yes, but that is not "normal operation" for an engine.
    will it prevent corrosion? probably yes it will, but normal 30/70 or 50/50 mix with water is also pretty good at preventing corrosion..

    rather than typing lots..